Analysis of speech signals of short pitch period by the sample-selective linear prediction

The conventional linear prediction analysis has difficulties in estimating the vocal tract characteristics of voiced sounds uttered by females or children. In this paper, it is shown that the vocal tract characteristics of those speech signals can be estimated accurately by the sample-selective linear prediction(SSLP) method proposed by the authors. The SSLP is a two-stage linear prediction analysis employing only relevant sample values in the second stage analysis while the conventional linear prediction method employs all the sample values with equal weights as predicted values. The accuracy of the proposed method in estimating formant frequencies is examined on synthetic vowels of short pitch periods. The validity of the method is confirmed by inspecting the estimated spectral envelopes and distributions of the estimated formant frequencies of natural vowels uttered by a female.